1. Field of the Invention
The invention relates generally to radiant thermal processing of substrates such as semiconductor wafers. More particularly, the invention relates to the lamp array used in producing the radiation for such thermal processing.
2. Background Art
Rapid thermal processing (RTP) is a term applied to several related high-temperature processes including annealing, dopant activation, oxidation, and nitridation among others. It can be further applied to etching and chemical vapor deposition in the presence of precursor or etching gases. RTP typically depends upon an array of high-intensity incandescent lamps fit into a lamphead and directed at the substrate or wafer. The lamps are electrically powered and can be very quickly turned off and on and a substantial fraction of their radiation can be directed to the substrate. As a result, the wafer can be very quickly heated without substantially heating the chamber and can be nearly as quickly cooled once the power is removed from the lamps. Thereby, the processing time at a predetermined temperature can be more closely controlled and the total thermal budget can be reduced. Furthermore, the total processing time can be reduced, thereby increasing throughput.